More than 9 of 10 companies in the Inc. 500 (91%) now use at least one social media tool.

That's up from 77% in 2008.

Think about the implications of this, which comes to us from a new study cited in Inc. magazine.

While experts have been vigorously debating the value of social media to business, major companies have been flocking to it.

Of the six social media categories covered in the survey, the one that continues to be the most familiar to Inc. 500 companies is social networking, with 75 percent saying that they are "very familiar with it."

Of those sites that currently comprise social networking, the top choice among the Inc. 500 was Twitter, which is used by 52% of respondents.